package com.ysten.basic.common.redis;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.TimeUnit;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.common.util.concurrent.ThreadFactoryBuilder;

/**
 * 线程相关工具类.
 * 
 * @author 陆小凤
 */
public class Threads
{
    
    /**
     * sleep等待, 单位为毫秒.
     */
    public static void sleep(long durationMillis)
    {
        try
        {
            Thread.sleep(durationMillis);
        }
        catch (InterruptedException e)
        {
            Thread.currentThread().interrupt();
        }
    }
    
    /**
     * sleep等待.
     */
    public static void sleep(long duration, TimeUnit unit)
    {
        try
        {
            Thread.sleep(unit.toMillis(duration));
        }
        catch (InterruptedException e)
        {
            Thread.currentThread().interrupt();
        }
    }
    
    /**
     * 创建ThreadFactory，使得创建的线程有自己的名字而不是默认的"pool-x-thread-y"， 在用threaddump查看线程时特别有用。 格式如如"mythread-%d"
     */
    public static ThreadFactory buildJobFactory(String nameFormat)
    {
        return new ThreadFactoryBuilder().setNameFormat(nameFormat).build();
    }
    
    /**
     * 按照ExecutorService JavaDoc示例代码编写的Graceful Shutdown方法. 先使用shutdown, 停止接收新任务并尝试完成所有已存在任务. 如果超时, 则调用shutdownNow,
     * 取消在workQueue中Pending的任务,并中断所有阻塞函数. 如果仍然超時，則強制退出. 另对在shutdown时线程本身被调用中断做了处理.
     */
    public static void gracefulShutdown(ExecutorService pool, int shutdownTimeout, int shutdownNowTimeout,
        TimeUnit timeUnit)
    {
        pool.shutdown(); // Disable new tasks from being submitted
        try
        {
            // Wait a while for existing tasks to terminate
            if (!pool.awaitTermination(shutdownTimeout, timeUnit))
            {
                pool.shutdownNow(); // Cancel currently executing tasks
                // Wait a while for tasks to respond to being cancelled
                if (!pool.awaitTermination(shutdownNowTimeout, timeUnit))
                {
                    System.err.println("Pool did not terminated");
                }
            }
        }
        catch (InterruptedException ie)
        {
            // (Re-)Cancel if current thread also interrupted
            pool.shutdownNow();
            // Preserve interrupt status
            Thread.currentThread().interrupt();
        }
    }
    
    /**
     * 直接调用shutdownNow的方法, 有timeout控制.取消在workQueue中Pending的任务,并中断所有阻塞函数.
     */
    public static void normalShutdown(ExecutorService pool, int timeout, TimeUnit timeUnit)
    {
        try
        {
            pool.shutdownNow();
            if (!pool.awaitTermination(timeout, timeUnit))
            {
                System.err.println("Pool did not terminated");
            }
        }
        catch (InterruptedException ie)
        {
            Thread.currentThread().interrupt();
        }
    }
    
    /**
     * 保证不会有Exception抛出到线程池的Runnable，防止用户没有捕捉异常导致中断了线程池中的线程。
     */
    public static class WrapExceptionRunnable implements Runnable
    {
        
        private static Logger logger = LoggerFactory.getLogger(WrapExceptionRunnable.class);
        
        private Runnable runnable;
        
        public WrapExceptionRunnable(Runnable runnable)
        {
            this.runnable = runnable;
        }
        
        @Override
        public void run()
        {
            try
            {
                runnable.run();
            }
            catch (Exception e)
            {
                // catch any exception, because the scheduled thread will break if the excetpion thrown outside
                logger.error("Unexpected error occurred in task", e);
            }
        }
    }
    
}
